Producing oil or gas from formations adjacent salt domes

ABSTRACT

Oil and gas are produced by drilling into a salt dome and washing out a cavity until a boundary line between the salt and the formation is reached. Petroleum then flows into the cavity facilitating production.

United States Patent r191 Kurtis et al.

[451 Apr. 30, 1974 PRODUCING OIL OR GAS FROM FORMATIONS ADJACENT SALTDOMES Inventors: Soma Kurtis, Denver; James H.

Kennedy, Longmont, both of Colo.

Assignee: Marathon Oil Company, Findlay,

Ohio

Filed: Feb. 20, 1973 Appl. No.: 333,606

References Cited UNITED STATES PATENTS 3/1964 Blood 166/308 7/1967 Shocket al. 166/308 10/1967 Jacoby et al 299/4 2/1968 Knutson et al 166/308 11/ 1972 Jacoby 299/5 Primary ExaminerJames A. Leppink Attorney, Agent,or Firm-Richard C. Willson, Jr.; Joseph C. Herring; Jack L. HummelABSTRACT Oil and gas are produced by drilling into a salt dome andwashing out a cavity until a boundary line between the salt and theformation is reached. Petroleum then flows into the cavity facilitatingproduction.

3 Claims, 3 Drawing Figures NJECTED BRINE PRODUCING OIL OR GAS FROM FORMATIONS ADJACENT SALT DOMES BACKGROUND OF THE INVENTION 1. Field ofthe Invention Y The present invention relates to the field of wells,

classified in Class 166 of the Classification System of the UnitedStates Patent Office.

2. Description of the Prior Art The inventors are aware of no relatedprior art.

SUMMARY OF THE INVENTION ings, and then proceeding to wash a cavity atthe appro-, priate elevation corresponding to the formation, orformations, to be produced, until the boundary line between salt and theformation hasbeen reached. The shape of this cavity is controlled by useof a hydrocarbon or gas cap. The size of the cavity is controlled by thewashing rate, brine concentration, and location of fresh water inlet andbrine withdrawal.

One, or a multiplicity of cavities, can be developed at a time, givenreasonablevertical and horizontal distances of the formations from thebore hole, or by the use of directional drilling in the salt. Thepresent invention is a measured advantage over traditional processessince the size of the exposure to the formation can be increased atwill, thus facilitating production. A large cross section of theproducing formation can be exposed to the artificial cavity and theactual production casing will sit in clean and open surroundings. Sincesalt domes are formed by pushing up through surrounding layers, thecavity, when washed out to meet the hydrocarbon containing formation,will be high relative to the overall formation and will thus facilitateproduction from the formation. Additional brine or water may also becontinuously recycled or otherwise introduced into the formation tomaintain pressure and hydraulic displacement, thereby furtherfacilitating production. In addition, multiple production casings may beintroduced into the salt dome cavity to allow simultaneous production ofseparated gas and oil. Recycle of brine can eliminate disposal problems.The long settling time provided for oil within the cavity reduces needfor settlers and treaters.

Utility of the Invention The present invention is particularly useful inthe offshore production of oil and gas from a formation adjacent to asalt dome, but is also useful in on shore operations.

DESCRIPTION OF THE DRAWINGS FIG. 1 shows schematically, an oil andgas-containing formation adjacent to a salt dome. For clarity only asingle horizon is shown.

FIG. 2 shows schematically, the cavity washing and production apparatusof the present invention after insertion into the salt dome and afterwashing of the cavity has been completed.

FIG. 3 shows schematically, the use of multiple production casings forthe simultaneous production of separated gas and oil.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples:

EXAMPLE I In FIG. 2, an oil or gas-containing formation 10 is locatedadjacent to a salt dome 11. Production from the formation can befacilitated by drilling a hole into the salt dome down to the level ofthe gas/oil-containing formation. The hole is fitted with a casing 12,which is cemented into place and is equipped with washing and productionstrings 13 and 15. Casing 12 can serve itself as one of these conduits.A cavity 16 is then washed to desired shape and size under controlledconditions, by opening the valves 14 and injecting water through onecasing 13 and removal through the other casing 15, or

vice versa, until the boundary line between the formation and the saltdome is reached. Upon completion, oil and gas then flows into the cavityand is removed through casing 12, 13, or 15.

EXAMPLE II In FIG. 3, a cavity is formed in the same manner as in FIG. 2with the exception that two production casings are introduced into thesalt dome cavity instead of one. One production casing 17 is placedtoward the top of the cavity, the other production casing 18 is placedtoward the bottom, thereby allowing the simultaneous production ofseparated gas and oil from the cavity.

Modifications of the Invention It should be understood that theinvention is susceptible to a wide variety of modifications andvariations which will be apparent to a person skilled in the art upon areading of the present specification. All such variations andmodifications are to be taken as being within the spirit of the claimsappended hereto.

What is claimed is:

1. In a method for producing oil and gas, the improvement comprising incombination:

a. drilling at least one well into a salt dome communicating with ahydrocarbon-containing formation,

b. washing out a cavity in the salt dome until the boundary line betweenthe salt and the hydrocarbon-containing formation is reached,

0. allowing hydrocarbons from the formation to enter into the createdcavity,

d. withdrawing said hydrocarbons from said created cavity through saidwell.

2. A method of production of oil and gas according to claim 1 wherein amultiplicity of production casings are introduced into said salt domecavity, said casings terminating at different heights to allowsimultaneous production of separated gas and oil.

3. A method of production of oil and gas according to claim 1 whereinadditional brine or water is continually introduced into the formationto maintain pressure and hydraulic displacement of the hydrocarbons fromthe formation.

1. In a method for producing oil and gas, the improvement comprising incombination: a. drilling at least one well into a salt domecommunicating with a hydrocarbon-containing formation, b. washing out acavity in the salt dome until the boundary line between the salt and thehydrocarbon-containing formation is reached, c. allowing hydrocarbonsfrom the formation to enter into the created cavity, d. withdrawing saidhydrocarbons from said created cavity through said well.
 2. A method ofproduction of oil and gas according to claim 1 wherein a multiplicity ofproduction casings are introduced into said salt dome cavity, saidcasings terminating at different heights to allow simultaneousproduction of separated gas and oil.
 3. A method of production of oiland gas according to claim 1 wherein additional brine or water iscontinually introduced into the formation to maintain pressure andhydraulic displacement of the hydrocarbons from the formation.